The most common mistake that might cause this is the presence of blank spaces at the beginning and end of the fingerprint text under Admin-->Service Desk Security. Please ensure that there are no spaces before or after the fingerprint.
To update the Fingerprint, you can login to your account using the URL domain.freshservice.com/login/normal and by using your freshservice local credentials.
If the issue persists, please send an email to support@freshservice.com and we'll help you out.